Method for testing sealed



Patented Jan. 7, 1941 UNITED STATES PATENT OFFICE METHOD FOR TESTING SEALED CONTAINERS No Drawing. Application August 28, 1939, Serial No. 292,317

1 Claim.

The present invention relates to a method for testing sealed containers and more particularly to a method for testing the efiiciency of sealing of a sealed container.

One object of the invention is to enable a person in charge of a carton sealing operation, such as a carton filling and sealing machine, to readily determine whether or not containers bein operated upon are being sealed in a satisfactory manner.

Another object of the invention is to provide a convenient method for determining the approximate maximum amount of internal gas pressure that a sealed container is able to withstand.

The present invention is applicable to the testing of any conventional form of hermetically sealed container. According to a preferred method of carrying out the present invention, cartons made of folding paperboard and provided with top and bottom closing flaps on each of the walls thereof, will first have the flaps on one end of the carton sealed. The carton is then placed with the open end upright and a small quantity of some readily volatile material is introduced into the carton. This material may conveniently comprise solid carbon dioxide. Other forms of volatile materials may be utilized such as liquefied or solidified gases.

In applying a small quantity of frozen carbon dioxide to conventional sealed containers a preferred method is, as stated above, to seal one end of the container, this being done in any convenient way, such as on a conventional sealing machine; then, prior to the time that the containers are being filled with the product, or, if desired, subsequently to such filling, a pellet of frozen carbon dioxide is introduced into a selected one of the containers, or a pellet may be introduced more or less regularly into one container in every group of twenty-five to fifty containers or other convenientnumber being handled by the sealing machine. The container into which the pellet of frozen carbon dioxide has been introduced will then be allowed to be sealed in the ordinary way by the sealing machine and the operator will then take such carton out of the production line and immerse it in a suitable liquid such as water, the temperature of which is maintained above that of the solid carbon dioxide or other volatile material which has been introduced into the container. In the case of frozen carbon dioxide and water, so long as the water remains in a fluid condition, it is satisfactory for making the test as the vaporizing temperature of solid carbon dioxide is much below the freezing point of water.

As soon as the frozen carbon dioxide has been introduced into the container it will, of course, begin to evaporate, or volatilize, and, when the container has been sealed, the evaporation of the solid carbon dioxide will begin to form an internal pressure within the carton. This internal pressure will then increase, providing the container has been hermetically sealed, until evaporation of the entire pellet has taken place.

If the container has not been properly sealed, this fact will be made immediately known by the escape of bubbles in the water or other liquid used for immersion of the carton. The operator in charge of the sealing operation can then make whatever adjustment in the sealing process he deems necessary to produce anefliciently sealed container.

By computation it is possible to produce an approximate predetermined internal pressure within the carton by selecting a pellet of frozen carbon dioxide of predetermined weight, the weight being so selected relative to the internal volume of the container that it will produce a desired degree of pressure within the carton when the solid carbon dioxide has been completely volatilized.

While the foregoing description discloses a preferred manner of applying and utilizing the present invention, it is to be understood that certain changes may be made without departing from the spirit of the invention, and it is therefore desired that the present disclosure be considered in all respects .as illustrative rather than restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

A method for testing sealed cartons which comprises introducing within the carton prior to sealing thereof a small quantity of frozen carbon dioxide, sealing the carton, and subsequently immersing the carton in a suitable liquid maintained at a temperature above the vaporization point of the frozen carbon dioxide within the sealed carton whereby vaporization of such frozen carbon dioxide will produce a pressure condition within the sealed carton causing escape of gas through any aperture in the carton walls or closure and the consequent bubbling of such escaping gas through the immersing liquid.

ROY E. LOWEY 

